Fig. 1. Effects of Delta1 overexpression on Notch activation and keratinocyte differentiation. (A) Schematic representation of the Delta constructs. (B) Anti-DeltaD immunofluorescence staining of human keratinocytes transduced with DeltaFl. Bar, 20 µm. (C) Hes1 luciferase reporter activity (upper panel) in J2-3T3 cells transduced with empty vector (ev), or Delta constructs. Fold induction relative to Renilla control is shown. Mean ± s.e.m. of four experiments. Lower panels show western blot of lysates of J2-3T3 cells used in the luciferase assay, probed with anti-DeltaD and anti-actin (loading control) antibodies. (D) Clonal growth of keratinocytes transduced with empty vector or Delta constructs. (E) Clonal growth of WT keratinocytes on a feeder layer of J2-3T3 cells transduced with empty vector (ev) or Delta constructs. (F-H) Epidermis reconstituted on DED by keratinocytes transduced with empty vector (ev; F,I), DeltaFl (G,J) or DeltaDS (H,K). Sections were stained with H&E (F-H) or anti-keratin 10 antibody (green) with DAPI nuclear counterstain (blue) (I-K). Bars, 50 µm.